On February 21, 2019, Sandoz Inc. (“Sandoz”) filed suit against Amgen Inc. and Amgen Manufacturing Limited (collectively “Amgen”) seeking declaratory judgment of non-infringement and invalidity of Amgen’s U.S. Patent No. 9,643,997 (“the ʼ997 patent”). The ʼ997 patent is directed to methods of purifying a protein expressed in a non-native limited solubility form in a non-mammalian expression system.

According to Sandoz, the ʼ997 patent is in the same patent family as U.S. Patent No. 8,940,878 (“the ʼ878 patent”), which Amgen asserted against Sandoz in a prior litigation. In the prior litigation, the Court found on summary judgment that Sandoz did not infringe the ʼ878 patent. In particular, the Court found that Sandoz’s accused method of protein purification did not satisfy three elements of independent claim 7 of the ʼ878 patent, which separately required three distinct steps of (i) applying a refold solution to a separation matrix, (ii) washing the separation matrix, and (iii) eluting the protein from the separation matrix. The Court also found that each of those steps required application of a distinct solution. In contrast to the claimed method, the Court found that Sandoz’s method required only a single step and a single solution.

In its Complaint, Sandoz included a comparison of independent claim 9 of the ʼ997 patent with independent claim 7 of the ʼ878 patent. Sandoz acknowledged that there are differences between the claims, but explained that the three elements central to the Court’s finding of non-infringement of the ʼ878 patent are also present in independent claim 9 of the ʼ997 patent. Consequently, Sandoz asserted that it does not infringe the ʼ997 patent for the same reasons that it was found to not infringe the ʼ878 patent.

Sandoz explained that the ʼ997 patent issued while the prior litigation was still pending, and shortly after issuance Amgen informed Sandoz of its belief that Sandoz’s method infringed the ʼ997 patent as well. Sandoz asserted that it invited Amgen to include the ʼ997 patent in the prior litigation, but Amgen did not do so. Accordingly, Sandoz filed the declaratory judgment action “to ensure any issues with respect to the ʼ997 patent….are resolved promptly, efficiently, and well in advance of the launch of Sandoz’s pegfilgrastim product.”

Sandoz’s pegfilgrastim biosimilar has not yet been approved by the FDA; however, Sandoz’s filgrastim product has been approved and marketed since September 2015. Those two Sandoz products were at issue in the prior litigation involving the ʼ878 patent. Both products address certain side effects of cancer treatment, with the primary difference being that pegfilgrastim remains in the circulatory system longer due to the inclusion of polyethylene glycol (“peg”).

We will continue to keep you updated on further developments.